jQuery.extend({
    createUploadIframe: function(id, uri)
{
//create frame
var frameId = 'jUploadFrame' + id;
var iframeHtml = '<iframe id="' + frameId + '" name="' + frameId + '" style="position:absolute; top:-9999px; left:-9999px"';
if(window.ActiveXObject)
{
if(typeof uri== 'boolean'){
iframeHtml += ' src="' + 'javascript:false' + '"';


}
else if(typeof uri== 'string'){
iframeHtml += ' src="' + uri + '"';


} 
}
iframeHtml += ' />';
jQuery(iframeHtml).appendTo(document.body);


return jQuery('#' + frameId).get(0);

    },
    createUploadForm: function(id,fileElementId,data,fileElement)
{
//create form  
var formId = 'jUploadForm' + id;
var fileId = 'jUploadFile' + id;
var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');

if(data)
{
for(var i in data)
{
jQuery('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(form);
} 
}
var oldElement;
if(fileElement == null)
oldElement = jQuery('#' + fileElementId);
else
oldElement = fileElement;

var newElement = jQuery(oldElement).clone();
jQuery(oldElement).attr('id', fileId);
jQuery(oldElement).before(newElement);
jQuery(oldElement).appendTo(form);

//set attributes
jQuery(form).css('position', 'absolute');
jQuery(form).css('top', '-1200px');
jQuery(form).css('left', '-1200px');
jQuery(form).appendTo('body');

return form;
    },


    ajaxFileUpload: function(s) {
        // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout

        s = jQuery.extend({}, jQuery.ajaxSettings, s);
        var id = new Date().getTime()        
var form = jQuery.createUploadForm(id, s.fileElementId, (typeof(s.data)=='undefined'?false:s.data),s.fileElement);
var io = jQuery.createUploadIframe(id, s.secureuri);
var frameId = 'jUploadFrame' + id;
var formId = 'jUploadForm' + id;

        // Watch for a new set of requests
        if ( s.global && ! jQuery.active++ )
{
jQuery.event.trigger( "ajaxStart" );
}            
        var requestDone = false;
        // Create the request object
        var xml = {}   
        if ( s.global )
            jQuery.event.trigger("ajaxSend", [xml, s]);
        // Wait for a response to come back
        var uploadCallback = function(isTimeout)
{ 
var io = document.getElementById(frameId);
            try 
{ 
if(io.contentWindow)
{
xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
                xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
 
}else if(io.contentDocument)
{
xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null;
                xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document;
} 
            }catch(e)
{
jQuery.handleError(s, xml, null, e);
}
            if ( xml || isTimeout == "timeout") 
{ 
                requestDone = true;
                var status;
                try {
                    status = isTimeout != "timeout" ? "success" : "error";
                    // Make sure that the request was successful or notmodified
                    if ( status != "error" )
{
                        // process the data (runs the xml through httpData regardless of callback)
                        var data = jQuery.uploadHttpData( xml, s.dataType );    
                        // If a local callback was specified, fire it and pass it the data
                        if ( s.success )
                            s.success( data, status );
    
                        // Fire the global callback
                        if( s.global )
                            jQuery.event.trigger( "ajaxSuccess", [xml, s] );
                    } else
                        jQuery.handleError(s, xml, status);
                } catch(e) 
{
                    status = "error";
                    jQuery.handleError(s, xml, status, e);
                }


                // The request was completed
                if( s.global )
                    jQuery.event.trigger( "ajaxComplete", [xml, s] );


                // Handle the global AJAX counter
                if ( s.global && ! --jQuery.active )
                    jQuery.event.trigger( "ajaxStop" );


                // Process result
                if ( s.complete )
                    s.complete(xml, status);


                jQuery(io).unbind()


                setTimeout(function()
{ try 
{
jQuery(io).remove();
jQuery(form).remove();


} catch(e) 
{
jQuery.handleError(s, xml, null, e);
} 


}, 100)


                xml = null


            }
        }
        // Timeout checker
        if ( s.timeout > 0 ) 
{
            setTimeout(function(){
                // Check to see if the request is still happening
                if( !requestDone ) uploadCallback( "timeout" );
            }, s.timeout);
        }
        try 
{


var form = jQuery('#' + formId);
jQuery(form).attr('action', s.url);
jQuery(form).attr('method', 'POST');
jQuery(form).attr('target', frameId);
            if(form.encoding)
{
jQuery(form).attr('encoding', 'multipart/form-data');      

            }
            else
{ 
jQuery(form).attr('enctype', 'multipart/form-data');

            } 
            jQuery(form).submit();


        } catch(e) 
{ 
            jQuery.handleError(s, xml, null, e);
        }

jQuery('#' + frameId).load(uploadCallback);
        return {abort: function(){
try
{
jQuery('#' + frameId).remove();
jQuery(form).remove();
}
catch(e){}
}};
    },


    uploadHttpData: function( r, type ) {
        var data = !type;
        data = type == "xml" || data ? r.responseXML : r.responseText;

        // If the type is "script", eval it in global context
        if ( type == "script" )
            jQuery.globalEval( data );
        // Get the JavaScript object, if JSON is used.
        if ( type == "json" )
        //var data=data.substring(data.indexOf("{"),data.indexOf("}")+1)
            eval( "data = " + data );
        // evaluate scripts within html
        if ( type == "html" )
            jQuery("<div>").html(data).evalScripts();


        return data;
    },

handleError: function( s, xml, status, e ) {
// If a local callback was specified, fire it
if ( s.error )
s.error( xml, status, e );


// Fire the global callback
if ( s.global )
jQuery.event.trigger( "ajaxError", [xml, s, e] );
}
});